I too have done FMQ on a king sized quilt on my Bernina 150 and was satisfied with the quality, including stitch length (no BSR for such an early machine). But I had issues with always having to rotate the quilt to get the bulk of the quilt to the outside and even then, in the middle it was hard to achieve more than a 2" flat area to the right of my needle. So I purchased a Tiara II at a great price as the table had cosmetic damage that I didn't care about.
The Tiara truly made quilting so much easier. No more having to roll or accordian my quilt and I found that the stitch regulator made ruler work effortless (for me). I don't use the puck for non-ruler quilting and have gotten along very well with the Tiara.